Astigmatism in an eye is the result of two mutually perpendicular meridians of the anterior face of the cornea not having the same curvature, and a known method of correcting astigmatism consists in forming two incisions in the cornea perpendicularly to the most highly curved meridian, i.e. to the meridian with the shorter radius of curvature, said two incisions being disposed respectively on opposite sides of the optical zone.
Merlin ("Curved keratotomy procedure for congenital astigmatism"; Journal of Refractive Surgery, 1987; 3:92-97) has made arcuate incisions for the purpose of correcting astigmatism, by using a micrometer blade held manually while using visual guidance based on a mark previously made by means of a circular marker.
Nevertheless, it is difficult to make incisions of uniform depth by means of a blade that is merely held in the hand, and this is particularly true when said incisions are situated on a diameter that is small.
As a result, such arcuate incisions are little used.
An object of the present invention is to make it possible to form arcuate incisions that are sufficiently accurate to achieve results regardless of the dexterity of the surgeon.